The Dirty Dozen

Buying organic can get really pricey. So I think it is important to spend it where it counts. The fertilizers and pesticides that are used in some conventional produce can be harmful to ingest and cannot be washed off because they are often absorbed into the food. The EWG (Environmental Working Group) suggest that the following be bought organic every time.
peaches

apples

bell peppers

celery

nectarines

strawberries

cherries

pears

imported grapes

spinach

lettuce

potatoes

Of coarse it is the stuff we eat most often so, as always, apply where you can.
Good news though onions, avocado, frozen sweet corn, pineapples, mango, asparagus, frozen sweet peas, kiwi, bananas, cabbage, broccoli and papaya are the "cleanest". So they are fine to buy conventional if you have to choose.